Fire Foam B1 Gun Grade is a quick-setting fire rated, one part polyurethane foam which expands on application to yield up to 50 times the can contents. It is fire rated up to 4 hours in certain joint configurations. Areas of use: For Filling: gaps around pipe entries through walls, gaps around door & window frames, electrical wire chasing prior to plastering, deep joints prior to applying sealant or plaster and irregular gaps in stone, brick, concrete or plaster. Fixing: door frames, timber structures, window sills and thresholds and window frames Insulating: behind cladding to exterior walls, behind soffit and barge boards and in automotive applications